Strains of Limosilactobacillus reuteri are used as starter and bioprotective cultures and contribute to the preservation of food through the production of fermentation metabolites lactic and acetic acid, and of the antimicrobial reuterin. Reuterin consists of acrolein and 3-hydroxypropionaldehyde (3-HPA), which can be further metabolized to 1,3-propanediol and 3-hydroxypropionic acid (3-HP). While reuterin has been the focus of many investigations, the contribution of 3-HP to the antimicrobial activity of food related reuterin-producers is unknown. We show that the antibacterial activity of 3-HP was stronger at pH 4.8 compared to pH 5.5 and 6.6. Gram-positive bacteria were in general more resistant against 3-HP and propionic acid than Gram-negative indicator strains including common food pathogens, while spoilage yeast and molds were not inhibited by ≤ 640 mM 3-HP. The presence of acrolein decreased the minimal inhibitory activity of 3-HP against E. coli indicating synergistic antibacterial activity. 3-HP was formed during the growth of the reuterin-producers, and by resting cells of L. reuteri DSM 20016. Taken together, this study shows that food-related reuterin producers strains synthesize a second antibacterial compound, which might be of relevance when strains are added as starter or bioprotective cultures to food products.
- MeSH
- Anti-Infective Agents chemistry metabolism pharmacology MeSH
- Bacteria drug effects growth & development MeSH
- Fermentation MeSH
- Glyceraldehyde analogs & derivatives chemistry metabolism MeSH
- Glycerol metabolism MeSH
- Hydrogen-Ion Concentration MeSH
- Lactic Acid analogs & derivatives chemistry metabolism pharmacology MeSH
- Acetic Acid metabolism MeSH
- Lactobacillaceae chemistry growth & development metabolism MeSH
- Food Microbiology MeSH
- Propane chemistry metabolism MeSH
- Drug Stability MeSH
- Publication type
- Journal Article MeSH
The current tendency to limit the use of chemical preservatives in food and to extend the shelf lives of pro-ducts leads to increasing use of natural antimicrobials. Therefore, lactic acid bacteria and their metabolites are used in fermented products. Organic acids, carbon dioxide, ethanol, hydrogen peroxide, diacetyl, reuterin, bacteriocins and other substances produced by lactic acid bacteria exhibit good activity in inhibition of undesirable microbiota.
Five new strains of lactobacilli isolated from goatling's stomach were identified by molecular-biological approaches. Profiles of fermentable saccharides, Gram staining, and cell morphology were also determined. They were identified as Lactobacillus reuteri (strains KO4b, KO4m, KO5) and as Lactobacillus plantarum (strains KG1z, KG4). In DNA samples of all newly isolated L. reuteri strains as well as in L. reuteri E (Lreu E; originated from lamb), the part of gldC gene, coding large subunit of glycerol dehydratase, that is necessary for 3-hydroxypropionaldehyde (3-HPA; reuterin) production, was amplified using two designed primer sets. However, the 3-HPA production was revealed only in the strain Lreu E. It produced five- or ten-fold lower amount of 3-HPA in comparison with probiotic L. reuteri ATCC 55730 in aerobic or anaerobic conditions, respectively. Moreover, Lreu E completely lost its production ability after ca. five passages in MRS medium. The co-incubation of Lreu E, but not other L. reuteri isolates, with Escherichia coli re-induced 3-HPA production. In the case of L. reuteri ATCC 55730, the 3-HPA production increased more than four times after co-incubation with E. coli.
OBJECTIVES: An increased glucose utilization by aldose reductase (ALR-2) has been implicated in the pathogenesis of diabetic vascular complications. In this process, several mechanisms are involved, including the depletion of cofactors required for the action of antioxidant enzymes or endothelial NO synthase. In this study, the effect of a novel ALR-2 inhibitor JMC-2004 on hyperglycemia-induced endothelial dysfunction was studied. METHODS: Bovine aortic endothelial cells (BAEC) were treated with glucose (30 mM), JMC-2004 (0.01mM), or glucose and JMC-2004 for 24 h. The cells were then stimulated with calcium ionophore A23187 after which NO production was measured electrochemically using a porphyrine-coated carbon NO electrode. Nitrite concentrations were determined in the cell supernatants. The peroxyl and hydroxyl radical-scavenging activity of JMC-2004 was measured with luminol-enhanced chemiluminescence. The expression of eNOS was determined by Western blotting. JMC-2004 IC50 for ALR-2 was determined colorimetrically with D-glyceraldehyde as a substrate. RESULTS: Incubating the cells with 30 mM glucose strongly diminished A23187- induced NO production. Treatment with JMC-2004 restored NO production by 40% without affecting eNOS expression. This effect was probably antioxidantindependent, since JMC-2004 did not have any antioxidant capacity. JMC-2004 exerted high selectivity towards ALR-2. CONCLUSIONS: ALR-2 inhibition with JMC-2004 was able to abolish hyperglycemia- induced endothelial dysfunction in bovine aortic endothelial cells.
- MeSH
- Aldehyde Reductase antagonists & inhibitors MeSH
- Cell Line MeSH
- Calcimycin pharmacology MeSH
- Endothelium, Vascular pathology drug effects MeSH
- Electrochemistry MeSH
- Endothelial Cells pathology drug effects MeSH
- Phenols pharmacology MeSH
- Glucose pharmacology MeSH
- Glyceraldehyde metabolism MeSH
- Hydroxyl Radical metabolism MeSH
- Hyperglycemia pathology MeSH
- Enzyme Inhibitors pharmacology MeSH
- Luminescence MeSH
- Nitric Oxide metabolism MeSH
- Peroxides metabolism MeSH
- Pyrroles pharmacology MeSH
- Cattle MeSH
- Nitric Oxide Synthase Type III metabolism MeSH
- Blotting, Western MeSH
- Animals MeSH
- Check Tag
- Cattle MeSH
- Animals MeSH
- Publication type
- Research Support, Non-U.S. Gov't MeSH
- MeSH
- Carcinoma, Ehrlich Tumor drug therapy MeSH
- Neoplasms, Experimental drug therapy MeSH
- Glyceraldehyde pharmacology MeSH
- Carcinoma, Hepatocellular drug therapy MeSH
- Injections, Intraperitoneal MeSH
- Cricetinae MeSH
- Rats MeSH
- Culture Techniques MeSH
- Leukemia L1210 drug therapy MeSH
- Liver Neoplasms MeSH
- Antineoplastic Agents pharmacology MeSH
- Sarcoma, Yoshida drug therapy MeSH
- Neoplasm Transplantation MeSH
- Animals MeSH
- Check Tag
- Cricetinae MeSH
- Rats MeSH
- Animals MeSH
